There are many examples of functional structures or components that can provide, produce, or detect electromagnetic or electronic signals or other characteristics. One advantageous form for these structures is in the form of functional blocks, which can be discrete elements with a characteristic shape, such as a NanoBlock™ Integrated Circuit made by Alien Technology Inc. The functional blocks are typically objects, microstructures, or microelements with integrated circuits built therein or thereon. These functional blocks have many applications and uses. The functional components can be used as an array of display drivers in a display where many pixels or sub-pixels are formed with an array of electronic elements. For example, an active matrix liquid crystal display includes an array of many pixels or sub-pixels which are fabricated using amorphous silicon or polysilicon circuit elements. Additionally, a billboard display or a signage display such as store displays and airport signs are also among the many electronic devices employing these functional components.
Functional components have also been used to make other electronic devices. One example of such use is that of a radio frequency (RF) identification tag (RFID tag) which contains a functional block or several blocks each having a necessary circuit element. Information is recorded into these blocks, which is then transferred to a base station. Typically, this is accomplished as the RFID tag, in response to a coded RF signal received from the base station, functions to cause the RFID tag to modulate and reflect the incident RF carrier back to the base station thereby transferring the information.
Such RFID tags are being incorporated into many commercial items for uses such as tracking and authenticating the items.
Demand for functional components has expanded dramatically. Clearly, the functional components have been applied to make many electronic devices, for instance, the making of microprocessors, memories, power transistors, super capacitors, displays, x-ray detector panels, solar cell arrays, memory arrays, long wavelength detector arrays, phased array antennas, RFID tags, chemical sensors, electromagnetic radiation sensors, thermal sensors, pressure sensors, or the like. The growth for the use of functional components, however, has been inhibited by the high cost of assembling the functional components into substrates and fabricating final devices or end products that incorporate the functional components.
Often the assembling of these components requires complex and multiple processes thereby causing the price of the end product to be expensive. Furthermore, the manufacturing of these components is costly under current methods because of slow, inefficient, and wasteful uses of the technologies and the materials used to make these products.
For cost and form factor considerations, many electronic devices are being constructed with ever-smaller electronic components. In particular, devices like RFID transponders, electronic displays, active antennas, sensors, computational devices, memory, and a number of wireless devices rely on integrated circuits (ICs) as small a 1 mm on a side, with demand to decrease the size further. While the raw component cost of devices can decrease along with their size, assembly of the components into devices becomes more difficult and more costly as their size decreases. There is a need for technologies that enable the low-cost assembly of active components that are on the order of hundreds of microns on a side, or even smaller and making interconnections to these active components.
Technologies like Fluidic Self Assembly (described in previous patents, including U.S. Pat. No. 5,545,291) can be effective in placing small integrated circuits in precise locations on a substrate. Many electronic components, however, require further processing to be integrated into devices. In particular, making electrical contact to the integrated circuit is necessary in many cases. The integrated circuit may need to be electrically connected to other active or passive components, sensors, power sources, antennas, display elements, or other integrated circuits.
Presently, electrical interconnections can be formed using a variety of processes. As one example, lithographic processes can be used in which a conductive layer (such as a metal) are deposited across a device, and then etched back to form wires and interconnections. As another example, screen printing can be used to print wires and interconnects using conductive inks. While both processes can interconnect many devices at once, there are limitations. For example, both processes rely on precise knowledge of the location of the integrated circuit on the receiving substrate. If there is some uncertainty in the exact position of the devices, then misregistration of the wiring pattern may lead to devices that are not interconnected properly. This misregistration problem becomes more severe in cases where the devices are small, or if plastic webstock is used as the receiving substrate. In another example, in the case of printing methods like screen printing, ink bleed can lower yield by inadvertent connection between electrical traces. This problem becomes more severe as devices get smaller. Additionally, there may be limitations in the set of materials that are compatible with screen printing, so that some desirable conductive materials cannot be processed with screen printing.
There is thus a need for a processing technology that allows for the precise interconnection of small functional components on a variety of receiving substrate materials, whether these materials be plastic, metal foils, glass, paper, or fiber (cloth) materials. Alternatively, there is a need for electronic system designs that are tolerant of poorly-registered interconnections that readily enable the use of small functional components. There is a need for inventions that allow of the construction of electronic components and devices on a variety of different materials, in high volumes, and at low costs.